Propeller



Sept, LA, 1940.

G. E. RAsK 2,215,564

PROPELLER Filed July 5, 1939 2 Sheets-Sheet l ATTORNEYS.

24, 1940. G. E. MSK 2,215,564

PR OPELLER Filed .my 5. 1939 2 sheets-sheer 2 azfzewz'mk I N V EN TOR.

A TTORNEYS.

PatentedSept. 24, 1940 UNITED STATES PATENT OFFICE Paornmna Gubert E. naar, santa Barbara, cam. Appucauo July s, 1939, serial No. 282,890

, I Claim.

It is well known that the utility of a propeller for an airplane or other similar craft is impaired by air disturbances, due to the fact that the blades of the propeller, generally stated. are

located in a common plane, at right angles to the axis of the propeller shaft.

Thisinvention aims to provide a simple but useful construction wherein each shaft propeller blade moves, generally stated, in its own quantum l() of air, one blade being located abaft the other,

longitudinally of the shaft.

Another object of the invention is to provide a device of the class described which is adaptable to standard controlling mechanisms for varying l5 the pitch of the propeller blades.

It is within the province of the disclosure to improve generally -and to enhance the utility of devices of that type to which the present invention appertains.

With the above and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction A hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the accompanying drawings:

Fig. 1 shows in elevation, a device constructed apart, transversely, and longitudinally of the l Therefore, each blade turns in its own" shaft I.

n body of air, there is a minimum amount of air disturbance, and unusual eciency results. There 'may be as many or as few of the blades 2 as is required, four of them being shown in the present embodiment of theinvention,

45 although that number is not rigidly insisted upon. Although the propeller has been shown as adapted to promote longitudinal movement of the aircraft, it is of equal utility as a lifting propeller.

It should be understood that the invention is 50 not conned to a mechanism in which the blades 2 are xed. The invention may be employed, with equal utility, in the event that it is desired to have' the blades controllable. 'I'he invention has been shown as incorporated in the well- 55 known Hamilton controllable propeller. wherein (Cl. 17o-163) the control forces are carefully calculated, so as to be ample for the purpose, with no possibility of reaching suicient magnitude to cause failure of any of the parts. In operation, oil pressure is used to movethe blades toward the 5 low pitch position; whereas the blades are moved toward the high pitch position by centrifugal forces acting on the counterweights attached to the propeller blade brackets. With the controllable propeller, the oil pressure is obtained from 10 the engine.' and the flow of this oil is controlled by a manually operated valve. In one position,

the 4valve permits the oil to ow from the engine through the transfer rings to the lfront end of the engine shaft and out to the propeller cylinder. l5 In another position, it shuts off the ow from the engine, and allows the oil in the propeller cylinder to drain back to the engine pump.

In view of the foregoing explanation, those skilled in the art will understand how the invenzo vtion may be used when it is desired that the blades shall be controllable. a

The shank 3 of each blade 2 has rocking movement about an axis transverse to the axis of rotation of the engine shaft I, in a bearing I 25 assembled with the shaft I. To the shank 3 of each blade 2 is connected, bypa bracket 5, av counterweight 6 having -an arcuate slot 1, the slot of the outermost counterweight being adapted. to receive a projection 8 carried by a 30 yoke 9 forming part of a member I0 movable longitudinally of the shaft I, responsive to the inertia of the counterweight 6, or under oil pressure, responsive to a valve II under the control of an operator, as has been set forth hereinbefore.

Circumferentially spaced, rigid connections or arms Il, of different lengths, form part of the yoke 9 and carry projections l2, functioning like the projection 8, the projections I2 being re- 40 ceived inthe slots 'I of the counterweights, other than the one immediately adjacent to the yoke 8. The construction is such that a controllable change in the pitch of the propeller blades is brought about when the structure including the, member III, the yoke 9 and the connections I0 is shifted longitudinally of the engine shaft I.

The device is simple in construction, and whether embodied in a controllable mechanism,` or in any other device, will. be found thoroughly elc'ient to prevent air disturbances, and will consummatev the objects set forth in the opening portion of this specication. l

Having thus described the invention, what is claimed is;

In an aircraft propeller, a shaft, a plurality of blades, means for assembling the blades with the shaft, in transversely spaced relation longitudinally of the shaft, a member movable longitudinally of the shaft, arms of different lengths attached to the movable member and extended longitudinally of the shaft, eounterweights connected to the blades and extended longitudinally of the shaft, the counterweights being provided with slots which are acutely disposed with respect to the direction of movement of said member and the arms, and projections on the arms and slidably received in the slots of the counterweights, to rotate the blades about axes at right angles to the axis ofl rotation of the shaft, when said member is moved longitudinally of the shaft.

GILBERT E. RASK. 

